Now, to the two explosions, two homes gone in an instant this weekend, it's believed those explosions were triggered by gas leaks, about 30 miles apart. In west virginia, the shattered pieces of one home spilled into the street there, while near pittsburgh tonight, a half hour away, nothing is left of another home left splintered in the middle of the night. And with so many families relying on natural gas, tonight, the warning signs. Here's abc's marcy gonzalez now. Reporter: The force so powerful, it left a giant crater where a home once stood. Last night's explosion near pittsburgh injur two people and could be felt and heard for miles. It sounded like an airplane went down. I just heard this huge explosion. Reporter: While investigators work to determine the cause, just more than 30 miles away in west virginia, investigators believe it was likely a natural gas explosion that ripped this this home to shreds friday morning, killing 13-year-old hannah mozingo and injuring her parents and sister. We did everything together and I'd do anything to get her back. Reporter: Potentially damaging and dangerous natural gas incidents are common. According to federal data, on average, there have been more than four a week for the past 20 years. The most common warning signs? A rotten egg smell and a hissing or blowing sound. Officials say, if you notice those, get out of the house and call 911. For now, investigators say the area surrounding these two scenes are safe. The communities secured, but shaken by the toll both still seen and so deeply felt. Marcy gonzalez, abc news, new york.

This transcript has been automatically generated and may not be 100% accurate.